Galvanized steel behaviour in Ca(OH)2 saturated solutions containing SO4 ions

Abstract

In previous work on galvanized reinforcements in contact with Ca-containing highly alkaline media the authors have reported the existence of a threshold pH of 13.3 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://mathoid.scipedia.com/localhost/v1/":): \pm

0.1 below which the Zn in contact with such a medium is passivated, but at pH values above this it corrodes continuously until it totally disappears. In this paper, the influence of the presence of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://mathoid.scipedia.com/localhost/v1/":): SO_4
ions on the electrochemical behaviour of the galvanized has been studied.

It has been established that the precipitation of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://mathoid.scipedia.com/localhost/v1/":): CaSO_4

with takes place in the media studied makes that the pH never surpasses the value of 13.3 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://mathoid.scipedia.com/localhost/v1/":): \pm
0.1. This coincidence with the pH threshold previously reported for passivation of the galvanized bars allows conclude that the sulfates not only are innocuous with respect to the galvanized behaviour in media which simulate the concrete but they are beneficial.